Certain s-triazines have been found to enhance nitrogen uptake and metabolism and thereby increase grain yields under some circumstances (see, for example, C. J. Schweizer and S. K. Ries, Science 165, 73-75 (1967).
The s-triazinediones used in this invention and their use as herbicides are disclosed and claimed in copending U.S. Pat. application Ser. No. 301,853, filed Oct. 30, 1972, by Fuchs and Lin, now U.S. Pat. No. 3,855,219 (which is a continuation-in-part of U.S. Pat. application Ser. No. 268,767, filed July 3, 1972, which is in turn a continuation-in-part of U.S. Pat. application Ser. No. 181,202, filed Sept. 16, 1971, both now abandoned). The use of these compounds in a method for altering plant flowering and sexual reproduction is disclosed and claimed in copending U.S. Pat. application Ser. No. 301,852, filed Oct. 30, 1972, by Fitzgerald and Long, now U.S. Pat. No. 3,898,073. Finally, the use of these compounds in a method for increasing crop yields is disclosed and claimed in copending U.S. Pat. application Ser. No. 446,801, filed Feb. 28, 1974, by James D. Long, now U.S. Pat. No. 3,901,682 (which is a continuation-in-part of U.S. Pat. application Ser. No. 414,878, filed Oct. 12, 1973, which is in turn a continuation-in-part of U.S. Pat. application Ser. No. 348,320, filed Apr. 5, 1973, both now abandoned).
In particular, in U.S. Ser. No. 446,801, there is claimed a method for increasing the yield of wheat, rye, and corn crops comprising applying certain s-triazinediones to the crop plant during inflorescence initiation or early development.
It has now been discovered that rice crop yields can be significantly increased by applying certain of these s-triazinediones to rice seed, to rice seedlings, or to the soil into which these seeds or seedlings have been or will be placed.